Java SE (Java Platform, Standard Edition)

Hi,

I developed a java app, which I want to distrubute. The app contains:
1)*.class files
2) a /sound directory with sounds files
3) a /images directory with images.

The things I am interested in are:
1) If I use jar to package everything, should I modify my code, so that it will correctly locate the sound and image resources? ( I am using File and URL to locate the images and the sound files)

2) What would be a good way to prevent my code from being reverse engineered

2A) How can I implement a mechanism where the program once installed will be operational for say 30 days and afterwards, will require a licence key of some kind to operate?

3) If I use jar to package everything, will I be able to use InstallShield to create an installer for the game?

Thank you